1. Field of the Invention
The present invention relates to a numerical control apparatus having a plurality of display attributes. Particularly, the present invention relates to a numerical control apparatus having a numeric data display function for displaying the position of a feed rod or the rotation speed of a rotational shaft based on display attributes according to working conditions of the feed rod or the rotational shaft.
2. Description of the Related Art
Numeric data on a display apparatus is displayed based on a combination of predetermined display attributes. The numeric data includes, for example, data indicating working conditions of a machine, such as, the position of the feed rod and the rotation speed of the rotational shaft. In addition, data indicating the working conditions of the feed rod, such as, a motor load, a cutting feed or a rapid traverse, are converted into numeric values and used as the numeric data. Meanwhile, the display attributes include, for example, display position, display color, variable density, and character font. A plurality of combinations of the display attributes for one piece of the numeric data are prepared. By so doing, it is possible to switch between a plurality of image displays prepared in accordance with specific purposes, such as, displaying a few pieces of the numeric data using large characters if priority is given to visibility and displaying many pieces of the numeric data using small characters if priority is given to the amount of information.
FIG. 1 is a block diagram showing an example of a conventional numerical control apparatus having a numeric data display function. The conventional numerical control apparatus having a numeric value display function will now be described with reference to FIG. 1.
An input interpret section 2 interprets an input KEY from an input device 1 and sends a result as a display image designation SEL to a display attribute determination section 4. Here, the display image designation SEL is data for designating a specific display image from a plurality of display images. A display attribute information storage section 3 stores combinations of display attributes registered in advance for every display image. The display attribute determination section 4 extracts a designated display attribute ATT in accordance with the display image designation SEL from the combinations of display attributes stored in the display attribute information storage section 3. A working condition extraction section 5 detects working conditions of a machine such as the position of the feed rod or the rotation speed of a spindle, converts the conditions into numeric data DAT and sends of a spindle, converts the conditions into numeric data DAT and sends the numeric data DAT to a display control section 6. The display control section 6 outputs the numeric data DAT to a display unit 7 in accordance with the designated display attribute ATT.
FIG. 2 is a flowchart showing an example of the display process of the display attribute information storage section 3, the display attribute determination section 4 and the display control section 6 in FIG. 1. Display procedures of the prior art will be described with reference to the flowchart of FIG. 2.
First, the designated display attribute ATT in accordance with the display image plane designation SEL is determined from the combinations of display attributes stored in the display attribute information storage section 3. In FIG. 2, the designated display attribute ATT has a structure in which a plurality of arrangements consisting of display attributes for a plurality of numeric data are provided. If an arrangement consisting of the display attributes of respective numeric data is AT, the following expression (1) is obtained: EQU ATT=AT(0)+AT(1)+. . . +AT(i)+. . . +AT(imax) (1)
In the above expression (1), a subscript "i" specifies the numeric data and a symbol "imax" is a maximum value of the subscript "i", which corresponds to the amount of numeric data which can be displayed simultaneously (Step S201).
Now, an example of the structure of the designated display attribute ATT will be described with reference to FIG. 3. The designated display attribute ATT has an added structure in which four arrangements, that is, AT(0) consisting of display attributes for the present position of an X axis, AT(1) consisting of display attributes for the present position of a Y axis, AT(2) consisting of display attributes for the present position of a Z axis and AT(3) consisting of display attributes for the rotation speed of a spindle. Constituent elements of one arrangement are a plurality of display attributes, such as, name of the numeric data NAM, display color CLR, label name LBL, display position POS and display font FNT. The attribute AT(2) in the expression (1), for example, indicates the arrangement consisting of display attributes for a numeric data specified by the subscript i=2, and indicates that the display color is black that the name (label name) of an axis "Z" and the present position of the Z axis are outputted in a 64-dot character font from a coordinate (100, 300) on the image thereof. In this example, the name NAM of the numeric value AT(4) is blank, which indicates the end of the displayed numeric data.
Referring back to FIG. 2, the subscript "i" in the expression (1) is initialized to "0" (Step S202). It is then examined whether or not the name NAM of numeric data AT(i) consisting of the display attributes of the numeric data is blank (Step S203). If the name NAM of the numeric data is not blank, the numeric data is displayed based on the display attributes of AT(i) (Step S204). Thereafter, one is added to the subscript "i" and the process returns to the Step S203 (Step S205). If the name NAM of numeric data name NAM is blank, the display process is finished at the Step S203. Procedures from the Steps S201 to S205 are repeatedly carried out and present working conditions of the machine can be thereby displayed on the display unit 1.
FIG. 4 is an example of the display of the numeric data on the image by the process shown in FIG. 2. In FIG. 4, present positions of the X axis, the Y axis and the Z axis as well as the rotation speed of the spindle axis are displayed as a black, 64-dot font based on the display attributes shown in FIG. 3, respectively. The above description refers to the conventional numerical control apparatus having a numeric data display function.
If an operator is away from the display unit to confirm a cutting condition and the image is displayed using large characters, as shown in FIG. 4, in consideration of the visibility from a distance, the information obtained at one time is disadvantageously limited. It is, for example, impossible to confirm the motor load conditions of the feed rod and the rotation shaft from the display of FIG. 4. This makes it necessary for the operator to leave the working place to change the image display, thereby wasting excessive time and labor of the operator.
Conversely, if the amount of numeric data displayed simultaneously is increased on the image display to obtain more information from the display unit, it is necessary to use small characters for displaying the respective numeric data. This makes it difficult for the operator to confirm the numeric data from a position away from the display unit and, therefore, the operator is more likely to misread the displayed values.